Cell Fracture Add-On Automatically Decimates Base Mesh
Sorry for the late reply, but I have been running into this problem as well and managed to find a solution. I have a pretty high poly vase model I wanted fracture:

I run into the same problem you did, where the Cell Fracture add-on was decimating my model. It took me a while to figure out what was going on.

The answer to the problem lies in the settings menu for the add-on. I found it while fiddling around with the add-on and trying everything to try and fix the issue. Note that this is the newest version, and there is no checkmark that disables model simplification. However, by checking &quot;Debug-Boolean&quot;, the add-on, for some reason, will not simply your model. The other settings did not matter and you can still adjust them to your preference.

As you can see, there is a nicely fractured vase that is free of decimating. The debug option does come with the drawback that you have to apply the Boolean modifier on each generated piece if you want to manipulate them, as high geometry boolean interactions are very slow.
I don't know if the debug option was intended to disable simplifying, but it does, and it works. I don't understand why they removed the disable simplifying option from the newest build, but I hope it can be added back. Anyways, best of luck on your work!